Projectile fuse



2 ySheets-Sheetk 1 J. F. MCCASLIN PROJECTILE FUSE www mlllill (ju/Ombo@ flaw-LEE. F. M-Crl: ELSIlT-l.

. @M afmf/MM'M Aug. 23, 1949.

Filed May 7, 1945 Aug. 23, 1949. J. F. MccAsLlN PROJECTILE FUSE 2 Sheets-Sheet 2 Filed May '7, 1945 jme/Mw llames F'. ME Ea 5.1'111` GMM/Mango' Patented Aug. 23, 1949 UNITED STATES PATaNroFlc 2,479,582. PROJECTILEFUSE James F. McCaslin, Cleveland, l(')l'iio I "v` Application May 7, 1945, Serial No. 592,434

s claims. (el. v1oz- 81) (Granted under the act of IMarch 3, 1883, as amended April 30, 1928; 370 0.*G. 757) The invention described herein may be manufactured and used by or forV the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to an improved safety means for projectile fuzes of the types employed in rie grenades, rockets, and similar projectiles.

The primary object of the present invention is to provide a fuze having a delay arming means actuated by the gases propelling the projectile for arming the fuze during acceleration of the projectile to eliminate the danger of casual displacement of the ring pin after removal of the safety pin and before firing of the projectile, which can readily occur if the projectile is dropped from an elevation of approximately two feet.

VStill another object of the invention is to utilize the annular groove normally provided in ring pins of such fuzes for receiving a retaining element which is retracted out of engagement with said groove by means actuated by the propelling gases.

Other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, which illustrate the preferred embodiments thereof, and wherein:

Figure 1 is a longitudinal, substantially central sectional view of a portion of a rifle grenade and with the invention shown incorporated therein;

Figure 2 is a fragmentary sectional view, similar to Figure 1, and showing the safety means in a retracting position, for arming the fuze;

Figures 3, 4, and are cross sectional views of portions of the projectile taken substantially along planes as indicated by the lines 3 3, 4 and 5 5, respectively, of Figure 1;

Figure 6 is a longitudinal, substantially central sectional view of the firing pin shown detached from the fuze;

Figure '1 is a fragmentary sectional viewsimi lar to Figure 1 of a slightly modified form of the fuze;

Figure 8 is a top plan view of one element of the invention shown detached;

Figure 9 is an enlarged longitudinal sectiona view of another form of the invention, especially adapted for use in rocket type projectiles;

Figure 10 is an enlarged cross sectional view of the fuze taken substantially along a plane as indicated by the line Ill-I0 of Figure 9;

Figure 11 is a side elevational view of one element of the invention as shown in Figure 10;

tional.

Figure l2 is a bottom plan view of theY same;

Figure 13 isan elevational view of another part of the invention. A y

Referring more particularly to the drawings, wherein like reference characters designate like and corresponding parts throughout the several views, and referring particularly to Figures 1 to 6 and 8, I5 designates generally therrear,A portion of a rifle grenade including a launcher tube I6, a tail finvassembly I'I and a fuze, designated generallyl8.

VThe fuze I8 includesa housing I9V having a restricted ,forwardly extending nipple-20A which is externally threaded to engage a burster charge, not shown, and is internally threaded to receive aY primer detonator holderZI. The housingv I9y is provided with an axially disposed borel 22 which extends to adjacent the rear thereof and which opens into the nipple 20 and is, therefore, in cornmunication with the holder 2|. A ring pin 23 Yis slidably disposed in the bore 22 and is provided with a Ytapered forward projection 24 which is aligned with an opening in the rear end of the holder 2I for receiving said projection, when the firing pin is projected'forwardly and into engagement with a primer detonator, not-shown,`con tained in the holder 2l and whichis detonated thereby, in a conventional manner. A vmagnet 25 is seated in and projects from the rear -end of the firing pin 23, and the rear end portion, at least, of the housing I9 is formed` of va metalwhich is attracted by the magnet 23 so that said magnet will function to normally retain the iiring pin 23 in a fully retracted, rearmost position withinv the bore 22, as illustrated in "Figure 1. The body portion of the ring pin 23 is provided with an outwardly opening annular groove 26, intermediate of itsV ends, for receiving a conventional safety pinZ'I, which' is removably anchored in the housing I9, for holding Vthe firing pin in its retracted position. The parts previously de;- scribed, except tlievmagnet 25, are all conven- The gas actuated safety device comprisinglthje invention, designated 28, includes a sleeve or ring 29 which is disposed in the tube I6 and directly behind the housing I9 and which is suitably xed therein. The sleeve.29, at its rear edge, is'provided with an inturned annular flange 30, and as seen invFigure 5 a portion of the sleeve 29.is split and bent upwardly to form wings or lugs 3 I. The inner or rear edges of said lugs 3l. are inclined forwardly and upwardly in a direction away from the flange 30, for a purpose which willhereinafter become apparent. A disk'32 is loosely disposed in the sleeve 29 and is of suiicient diameter so that its peripheral portion will bear Y ush with the outer side of said flange as clearlyshown upon Fig. 1. When the disk 32 is thus dis-W posed, a portion thereof is arranged between thev inclined edges of the lugs 3l and agri-part o f the flange 30.

The housing I9 is provided .withla radiali bore 33 which opens outwardly thereof at one'of its 4 bore 22 to cause it to strike and detonate the primer, not shown, contained in holder 2l which will in turn d-etonate the burster charge, not shown. To prevent casual displacement of the retaining member 34, a shear wire 4Iv extends through 'a portion of the housing I9 and through anV opening in the retaining member 34. Said wire v4Il is sheared when-'retaining member 34 is forced outwardly by forward movement of the vplunger 38. As seen in Figure 4, housing I9 is .provided with longitudinal kerfsY 42 to facilitate insertion of the wire 4I.

ends and which has its opposite end opening into the bore 22 and communicating with the groove 26, when ring pin 23 isin a fully retracted position. A retaining element or detent 34 is reciprocally disposed inthe bore 33= and is provided with a bifurcated inner end 35 which extends into the groove 26 whenthe detent-34 isin a projected, operative position, as seenyin Figure/v1. The apex 33 of the bifurcatedportion 35'l is inclinedvforwardly and downwardly, as bestseen in Figure 2'. The housing I9 yis provided witha longitudinally extending bore -3'Iiwhich opens outwardly of the rear end'thereof andw-hich intersects'the bore 33 adjacent its forward-fend; A `rod' orplunger 38'i`s reciprocally disposed in the bore 31 Vandthe rear end` vthereof normally projects from therear face of the .housingY I97`an'dbe`a'rs against a part ett'hfeA disk 32 whioh'is substantially diametrically opposed Ato the portion thereof which is in proximity tothe lugs 3l, As bestseen in Figure 8, the opposite, forward end ofthe vplunger 38 Yis provided with a restricted extension 39, theA hori- Zontal width of Awhich is si'lbstantially less than the diameter of the, plunger 38. The vertical width o f the extension-3 9, 'adjacentt'o plunger 3,8,is approximatelyequal to the diameterof the rod 38, and therebeyond, the upper surface of the extension39isbevelled tolform a cam-surface 40, which is .disposed,atsubstantially the same angle as the inclined Vsurface 36; against which aportion `of surface Illv normally engages, as sierenin liligurew 1, The forward jendof the extension se is rounded sngnny t@ enebieit to more readilyengajge.underhthe,surface-36.

Assuming that Vthe safety pin 21 'has'been removed, the fuzoe VI8, will still be retainedin a safe or disarrned condition byvjth'e furcations 3 5 en*- Egi'ng in the. groove v26. When the projectile I5 isiired from'a 'riflelgrenade launcher in a Vconventional manner, thegexl'panding gases `of the propelling cartridefewillv impinge againstthe disk 3'2in the course ofpropelling the projectile from the Alauncher 'and in so doing will 'force fthe disk 32 `forwardly relatively to .the'sleeve 29.1 The f 4lugs 3l will provide ja fulcrum fordisk y32 upon winch the d'isigwiu rockgxrrom its position in Fi-g? ure 1 to its position inV Figure 2. vThis rocking movement of the .disk 32 willprojet the plunger mingengagement 'o'f the surfaces 36`and r`40 vthe retaining member 3 4 will be cammed outwardly relatively to the boreV 33 iandout of engagement with the groove 2li to release thering pin 23 l'and therebyl arm r,he,i`uzeV I8( After release of 'binrod'as forwardly. m the bore siena by cam- Th'e'embodiment of the invention shown in Figure 'lfdiffers from the form, previously described, only in that the magnet 25 is omitted, and 'in lieu thereof a helical spring 43 is disposed b'eilweenv the forwardend of the body portion of the firing pin V23 and the primer holder 2| and functions as a creep spring to retain the ring pin 23 in aA retracted position until impact of the projectile with its,target. Y

In the embodiment of the invention disclosed in Figures 9-13, 44 designatesfgenerally a portion offaprojectilef the rockettype including a tube 45 forming aportion of the motor chamber thereof. A fuze, designatedgenerally 46, includes a housing, Ythe rear endof lwhich issuitably anchored in'theforward end of thetube or motor chamber 45 and whichveontainsa ring p in 48 corresponding.totheiiring pin 23. andrheld by a manuallypremovable .safety pin 49, in the same manneras the safety pin-27:

An .obturating piston .50 1is `reciprocally disposed inthe enlarged forward partofthe tube.45. The bore of the tube 45 is restricted behind piston luto form aforwardly facing shoulder.. 5L between whichk and thehousng 4 'I the piston 5 0 is'slidablydisposed. Thehousing 41, as best seen in-'Figure 10, is provided with aslot 52,-which opensoutwardly. ofits periphery and which is provided with a restricted opening 53 which communicateswith theiiring pin boreand with the, annular groove@ 54;v of the firing pin=when inits fully, retracted position., In lieu of the re,- taining element-M thenfuze46 is provided lwith a strand of wire 55, one end of which is anchored ir; a recess 56y ofltheV-housinglll and which opens intov the slot; 52 .1 Theppposite end-,oi the wire`.55, arverne. nrst-menuonefiend 'has ,been anchored in the recess 5'6, is bent into substantially hooked shaped formoas seen jat-157Landra terminal 'orfbill 55 -ftesr-.epf DrOJePtS through thev Opening 53 A and into thel tg-rooye 54., The ,housing 4l.. is provided withna .longitudinallyextending bore 5 9`whichi`n'- terseots the-A' transversely disposed` slot 52 ajnclcin 'nnsr'side 0fthegpsten, headff'fhe opposite for: ward end of the rod or plunger Bil is tapered vto forma conical point 673, the bottom part of which forms an elongation of 4the lbottom portion of the plunger 69. The Vforwardend ofthe -fcone 63 engages under thek arcuate innerside 54f1of -the hook'EfI; i

AssumingV that --the safety pil-n 49 had -b'een re- /Inovedgand the Vproiestile--44 isi fired fromA suitable launchingmeans, notshown,the-propelling gases thereffwill -impinge against theflinneinor rear side oflgthevheadicf.:the:pistonSilvas-.the proj e'ctile isaceelerated tmthusf-drivemthe piston 'I5 50 forwardly against the rear end of the housing 41. `This will cause theconical lportion 63 to move through the inner portion of the hook 51 to cam or wedge the terminal 58 thereof out of engagement-With the groove 54, through the camming engagement of the conical portion v63 with the arcuate portion 64 of the hook'51. As a result, the firing pin i8 will be released to be actuated upon impact of the projectile 44 with a target in the same manner that the firing pin 23 is projected by inertia, as previously explained. The strand or rod.55 is bent into the form shown in Figure 10 upon being applied to the housing 41 and in Figure 13 is shown in its initial Vshape before application` to the housing.

Various other modications and changes are `likewise contemplated and may obviously be resorted to, without departing from the spirit and scope of the invention as hereinafter defined by the appended claims, as only preferred embodiments thereof have been disclosed.

I claim:

1. In a fuze for a rifie grenade, a housing having a central axial bore opening forwardly through said housing, a firing pin slidably fitting said bore and movable therein from a safe toa firing position, a detent movably mounted in a firstY radial hole in said housing opening into said bore, the inner end of said detent normally engaging said firing pin to retain the same in safe position, a tube, said housing fitting and being .rigidly secured to the forward end of said tube, a release rod slidably mounted in a second hole in said housing, said second hole being parallel with and laterally offset from said bore and opening through the rear face of said housing and intersecting said first hole, a piston movable in said tube and operable to slide said rod from a first to a second position in response to gas pressure incident to firing of said grenade, said detent and said rod having interengaging cam surfaces effective to move said detent radially outwardly out of engagement with said firing pin when said rod is moved to second position.

2. In a fuze for a rifle grenade, a housing having a central axial bore opening forwardly through said housing, a firing pin having a circumferential channel and slidably fitting said bore, a detent movably mounted in a first radial hole in said housing opening into said bore, the inner end of said detent normally entering said channel to retain said firing pin in safe position, a tube, said housing fitting and being secured Within the forward end of said tube, a release rod slidably mounted in a second hole in said housing, said second hole being laterally offset from and parallel with said bore, opening through the rear face of said housing and intersecting said first hole, a piston movable in said tube and operable to slide said rod from a first to a second position in response to gas pressure incident t0 firing of said grenade, said detent and said rod having interengaging cam surfaces effective to move said detent out of said channel when said rod is moved to second position.

3. A fuze for projectiles of the rie grenade and rocket type, comprising, a piston movably disposed in a projectile and arranged to be actuated by the propelling gases thereof, said projectile having a fuze including a housing and a firing pin slidably disposed therein, said firing pin having an outwardly opening recess formed therein, a retaining member slidably mounted in an aperture in the housing and norm-ally engaging in said firing pin recess to retain said firing @gaat fiange.

pin in safe position, means actuated by the piston and engaging the retaining member for moving the retaining member out of engagement with the firing pin when the piston is actuated by the propelling gases, and a sleeve having an annular inturned flange at one end thereof in which the ,piston 'is disposed, said piston constituting a disk the peripheral portion of which engages against said flange and the remaining portion of which substantially closes the opening formed by the ing an outwardly opening recess formed therein,

'a retaining member slidably mounted in an aperture in the housing and normally engaging within said firing pin recess for retaining the firing pin in, a safe position, means actuated by said piston and engaging said retaining member for moving the retaining member out of engagement with the firing pin when the piston is actuated by the v propelling gases, and a sleeve having an annular inturned ange at one end thereof in which said piston is disposed, said piston comprising a disk the peripheral portion of which engages against said flange and the remaining portion of which substantially closes the opening formed by the flange, said disk being dished, the dished portion extending into the fiange opening and substantially filling the same.

5. A fuze for projectiles of the rifie grenade and rocket type comprising a piston movably disposed in a projectile and arranged to be actuated by the propelling gases thereof, said projectile having a fuze including a housing and a firing pin slidably disposed therein, said firing pin having an outwardly opening recess formed therein, a retaining member slidably mounted in an aperture in the housing and normally engaging within said firing pin recess for retaining said firing pin in a safe position, means actuated by the piston and engaging said retaining member for moving the retaining member out of engagement with the firing pin when the piston is actuated by the propelling gases, and a sleeve having an annular inturned flange at one end thereof in which the piston is disposed, said piston constituting a disk the peripheral portion of which engages against said fiange and the remaining portion of which substantially closes the opening formed by said flange, said sleeve having an inwardly projecting lug spaced from the flange and against which a portion of the disk bears to cause said disk to rock in the sleeve and on the lug as a fulcrum when actuated by the propelling gases, and the piston actuated means bearing against a portion of the disk which is substantially diametrically opposite to the portion engaging the lug.

6. In a fuze for projectiles, a housing having a central axial bore opening through the forward wall of said housing, a firing pin slidable in said housing from a first safe position to a second firing position, a wire having a straight shank anchored in said housing and a hooked end extending inwardly into said bore in the path of said firing pin to retain the same in first position, a tube, said housing being rigidly mounted in and sealing, the forward end of said tube, a piston slidable in said tube, and means engaging the inner periphery of the bowed portion of the 

